h a l f b a k e r yFewer ducks than estimates indicate.
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They make multi-stage rockets because the extra sections drop off as it flies to reduce dead weight.
The casing of the unraveling rocket would be spiral wound and would behave somewhat like a TOW missile as it unspools...Just unravelling the extra weight as it flies, rather than dropping off sections.
Piston_20Rocket
[spidermother, Oct 31 2012]
Case bonding, and why it's usually not done
http://www.nakka-ro...y.net/casebond.html
[spidermother, Nov 01 2012]
[link]
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Hang on a moment. Rockets normally burn from the
bottom upwards. The bottom end is important,
because it carries the nozzle. So... |
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It's propelled by wool dust. |
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[MB] this would of course work on your syringe-rocket, except for the bit where it doesn't work. |
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(lyrics) "If you want to destroy my sweater, pull this thread as I walk away..." |
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In order for the combustion chamber to be strong enough, the drag due to unwinding would be huge. |
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The rocket would be built of solid fuel, with the nozzle climbing up the spiral body of the rocket, consuming it and turning it into pure thrust as it went. |
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Most solid fuel rockets don't burn bottom-to-top like that (it's called the end burner configuration, and it's considered difficult and dangerous). But it can be done. |
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Well, if they don't burn from the bottom up, they
burn from a central hole out. Either way, a rocket
needs to keep its arse. |
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Actually, I quite like [bungston]'s idea. If you had
a solid stick of propellant, with a cap on the top
and a cap on the bottom with a nozzle, and with
some very very very powerful springs holding the
two together... no, it still wouldn't work but it's a
nice idea. |
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If it were a liquid rocket, you could make the
tanks telescopic so they'd shorten as the fuel was
consumed. But then you wouldn't be saving any
weight. |
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//if they don't burn from the bottom up, they burn from a central hole out// Very often, the grain burns from all sides, including the outer surfaces (but often including a central hole). Mainly because if you design it to work any other way, a failure of the bond with the casing (or other means of preventing burning of the outside surface) greatly increases the burn rate, which is a Bad Thing. |
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This I didn't know. Is the combustion of solid fuels
at a similar temperature to that of liquid
(lox/kerosene) mixes? Liquid rocket combustion
chambers are usually actively cooled, but in a solid
rocket the whole damned thing is a combustion
chamber. |
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//This I didn't know.// (Link) to the superb site where I learned this, and nearly everything else I know about small rockets. |
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Liquid rockets burn hotter, in general, which is consistent with their higher specific impulse. |
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